The present invention relates to hand impact tools and their handles. In particular, it is concerned with shock-absorbing handles that are flexible in one direction but not in the other.
The traditional hickory hammer handle has been successfully employed for a long time and is still reasonably popular. However, the relative costs of the hickory and competing materials, as well as some favorable characteristics of the competing materials, have resulted in a trend away from the traditional handle.
Even before this relatively recent trend away from the traditional handle, some reevaluation of the desirable characteristics of a hammer handle had occurred. Specifically, it was recognized that it may not be desirable for the hammer hanlde to be excessively rigid, because an excessively rigid handle tends to transmit shock to the handle of the user. This shock can be annoying over the short term and can have damaging effects on the hand over the long term. Accordingly, it has been found desirable to reduce the shock transmitted by the handle as much as possible, and handles that flex upon impact have been designed as a result.
Although it is desirable to have the hammer handle flex upon impact, flexing at other times is sometimes undesirable. For instance, it is preferable for the hammer not to flex when the claw on a claw hammer is being used. Consequently, a number of designs have been proposed that permit flexing in one direction but not in the other. Forbes U.S. Pat. No. 1,794,008, for example, illustrates in FIG. 1 a hammer handle that is hollow and is spring loaded to permit flexing in one direction but not in the other. The use of a hollow handle has quite apparent drawbacks, however. One of the more recent developments in this area is illustrated by U.S. Pat. Application Ser. No. 056,721 of Whiteford, which employs vertebra members that are individually rigid but flex in one direction when assembled into a column. The Whiteford arrangement substantially avoids the hollow construction of the Forbes hammer but requires a multiplicity of vertebra members.
It is the object of the present invention to provide the one-way flexure of Forbes and Whiteford without the hollow construction of Forbes or the number of parts required by Whiteford.